Automatic feeding device



Aug. 18, 1970 $M|TH ET'AL AUTOMATIC FEEDING DEVlCE 5 Sheets-Sheet 1 Filed March a, 1968 INVENTORS' RICHARD E. SMITH PAUL S. HEILER FRANKLIN Aug. 18, 1970 R, 5 H ET AL 3,524,639

AUTOMATIC FEEDING DEVICE Filed March 8, 1968 5 Sheets-Sheet 2,

INVEN-TQRS' RICHARD E.. MITH PAULS HE "ER BY FRANKLIN LQl-(EAD Arrow/2r Aug. 18, 1970 R, sMlTH ET AL 3,524,639

AUTOMATIC FEEDING DEVICE Filed March 8, 1968 5 Sheets-$heet 4 INVE RICHARD EfERMTH PAUL S. HEILER BY FRANKLIN L.H.EADD

A 7' TORNEV Aug. 18, 1970 s n-H ET AL 3,524,639

AUTOMATIC FEEDING DEVICE Filed March 8, 1968 5 Sheets-Sheet 5 mvENm'R RICHARD E. sMlf'H PAUL S. HEILER BY FRANKLIN L.HEADD AT NE) United States Patent O 3,524,639 AUTOMATIC FEEDING DEVICE Richard E. Smith, Webster, Paul S. Heiler, Fairport, and Franklin L. Headd, Webster, N.Y., assignors to Xerox Corporation, Rochester, N.Y., a corporation of New York Filed Mar. 8, 1968, Ser. No. 711,547

Int. Cl. B65h 3/06 US. Cl. 271- 8 Claims ABSTRACT OF THE DISCLOSURE Sheet feeding apparatus for separating a sheet from a stack and positioning it at a point for delivery to a facsimile transceiver on request wherein a pivotably mounted kicker roller advances the top most sheet in the stack into a separating means, withdraws from the stack for a delay period to insure separation of superposed sheets and momentarily engages the forwarded sheet a second time to assist the separating means to advance the separated sheet to a point beyond the separating mechanism.

BACKGROUND OF THE INVENTION The present invention relates to sheet handling apparatus and in particular to apparatus for serially feeding sheets from a stack.

Sheet feeding apparatus are commonly employed with sheet processing systems that require feeding of sheets one at a time to permit operations to be performed on the individual sheets at a series of operation stations within the system. Systems of this type are normally sensitive to simultaneous feeding of more than a single sheet and have detection means to automatically shut down the operation of the system when a multiple sheet feed occurs. The systems are able to process large quantities of sheets in relative short periods of time providing the flow of sheets through the system is not interrupted. A multiple sheet feed, i.e. the introduction to the system of two or more overlapping sheets, often interrupts the flow of sheets through the system resulting in costly shutdowns of the system. In many systems, the mechanical tolerances of the sheet path permit the passage of only single sheets and overlapping sheets jam the sheet path causing a shut down. In addition, sheet processing systems commonly employ switches to locate the position of sheets along the sheet path to time the movement of a sheet from one operation station to the next. A multiple sheet feed causes the switches to give false indications as to the location of a sheet, thereby giving rise to sheet jams and other malfunctions leading to the shut down of the system.

The present sheet feeding apparatus attacks the problems resulting from multiple sheet feed by increasing the reliability of sheet feeding apparatus. Improved sheet feeding apparatus is obtained by increasing the efficiency of sheet separating mechanisms and by positioning a sheet separated from a stack at a point where it is available for immediate delivery to a sheet processing system.

It is accordingly an object of the present invention to improve sheet feeding apparatus.

Another object of the present invention is to improve in sheet feeding apparatus the feeding of single sheets from a stack.

Still another object of the present invention is to feed a single sheet from a stack in response to an external command.

It is a further object of the present invention to separate a single sheet from a plurality of sheets and to position the separated sheet at a location Where it is immediately available to an external system.

A still further object of the present invention is to feed the top sheet from a stack while restraining the feeding of superposed sheets with the top sheet.

Yet another object of the present invention is to increase the efiiciency of sheet separating apparatus.

SUMMARY OF THE INVENTION The present sheet feeding apparatus forwards the top sheet from a horizontal stack of sheets to a sheet processing system while restraining or preventing superposed sheets in the stack from advancing along with the top sheet. A retractable kicker roller intermittently engages the top sheet in the stack to forward the top sheet into a separating or routing mechanism. The routing mechanism operates on the top sheet as well as superposed sheets forwarded by the kicker roller along with the top sheet. The routing mechanism advances the top sheet along a feed path to a position for immediate delivery to the sheet processing system and returns the superposed sheets backward toward the stack of sheets. A switch indicates when sheets are under the influence of the routing means and generates a signal to remove the kicker rollers from the stack and to stop the advancing means in the routing mechanism. Removing the kicker roller from the stack and stopping the advancing means assists the routing means to return superposed sheets toward the stack.

DESCRIPTION OF THE DRAWINGS FIG. 3 is a right elevation sectional view of the sheet feeding apparatus.

FIG. 4 is a plan view of the sheet feeding apparatus.

FIG. 5 is an end view of the sheet feeding apparatus.

FIG. 6 is an isometric view of the sheet feeder drive mechanism.

DETAILED DESCRIPTION OF THE INVENTION The sheet feeding apparatus is shown coupled to fac simile transceiver 300 in FIG. 1. On command from logic circuitry (not shown) in the transceiver 300, sheet feeder 200 separates the top sheet from stack 210 and advances it to the transceiver where it is placed on platen 302 by transceiver sheet rollers 301. Thereafter, the transceiver commands feeder 200 to separate a second sheet from the stack and to deliver the sheet to a point short of rollers 301. The first sheet loaded on platen 302 is fed through the transceiver and when it clears platen 302 the transceiver directs feeder 200 to advance the sheet held short of rollers 301 onto platen 302. After the second sheet is placed on the platen, the feeder again advances a sheet to a point short of transceiver rollers 301. The sheet feeder functions in this manner on subsequent sheets, loading a sheet onto platen 302 when requested by transceiver 300.

A sheet on platen 302 is advanced past scanning station 303 where graphic information on the sheet is translated into electrical signals by electrical-optical means and transmitted to a remotely located transceiver. The sheet continues past the scanning station to platen 304. Thereafter, the sheet is fed from platen 304 to collecting tray 307.

The operation of transceiver 300 is impaired by the simultaneous feed of more than one sheet into its paper path. A double paper feed, for example, can lead to a paper jam and a resultant shut down of transceiver 300. It is therefore the responsibilty of the sheet feeding apparatus of the present invention to insure the delivery of a single sheet to the transceiver on request.

The sheet feeder is constructed in modular form. The sheet feeder designation 200 in FIGS. 1, 2 and 3 also designates the module. The module is adapted to slide on rails (not shown) mounted in the transceiver on mating tracks 270 shown in FIG. 2. Electrical connector 265 (FIG. 3) is mounted in the rear of the module. The connector mates with a compatible connector mounted in the transceiver when the module is slid on the rails into a fully inserted position in the transceiver. All electrical connections to the feeder, including those from the transceiver logic circuitry, are made through connector 265.

Referring to FIG. 2, sheet feeder tray 220 supports a stack of sheets to be fed to the transceiver. The right and left margins of the stack are adjusted by sliding right margin guard 221 and left margin guard 222 into contact with the stack. The margin guards move along paths established by slots 224 out into the bottom of tray 220. The guards are held in place by tension exerted by bars 235 shown in FIG. 3. Each guard is rigidly attached to a bar 235 at brackets 237 and 238 that extend through the slots. The radius of roller 236 attached to the bar is greater than the distance the bar is mounted below the tray. The resultant bend imparted to the bar provides the force necessary to hold the guards in a fixed position. The force exerted by the sprin gaction of the bar can be overcome by hand, thereby permitting the margin guards to be adjusted for positioning a stack relative to the kicker rollers.

Rotary solenoid 250 (FIG. 2) is normally energized thereby maintaining kicker rollers 201 in a raised position. This facilitates the insertion of sheets into tray 220. The kicker rollers initiate the separation of a sheet from a stack. The energizing of solenoid 250 as well as the application of power to the various rollers in feeder 200 (discussed later) is controlled by the logic circuitry in the transceiver. When the solenoid is energized, the kicker rollers 201 are raised by arm 251. The arm is coupled to the shaft of solenoid 250 and as it rotates it contacts extension 254 on kicker roller carriage 252, thereby lifting the carriage and kicker rollers to a raised position. When solenoid 250 is de-energized, the carriage is lowered bringing the kicker rollers into contacts with a stack of sheets in tray 220. Counterbalance 253 is adjustable thereby permitting the pressure exerted by the kicker rollers on a stack to be varied.

Apparatus used to adjust counterbalance 253 is shown in FIG. 4. Sleeve 256 is coupled to shaft 259 about which the kicker roller carriage 252 is pivoted. Extending through sleeve 256 is arm 255 which supports counterbalance 253. Sleeve 256 may be rotated on shaft 259 by releasing a set-screw (not shown) used to lock the sleeve to shaft 259. Rotating the sleeve on shaft 259 enables the gravity vector of the counterbalance to be varied thereby changing the pressure exerted by the kicker rollers on the stack of sheets. When arm 255 is positioned in a horizontal plane the kicker rollers exert minimum pressure on the sheets and when arm 255 is positioned in a vertical plane the kicker rollers exert maximum pressure of the sheets.

The kicker rollers follow an arcuate path as carriage 252 pivots about shaft 259. Consequently, the kicker rollers tend to shingle the sheets in the stack as they are lowered into engagement with the stack. The shingling of the sheets imparts an initial separation of the sheets from the stack. The shingling action is assisted by abutment 208 (FIG. 3). The slope of the abutment tends to shingle the sheets as they are urged forward by kicker rollers.

The sheet separating apparatus of the present feeder includes feed rollers 202 and retard rollers 203 which are positioned relative to each other to form a bite through which sheets are fed. The feed and retard rollers 202 and 203 respectively are laterally offset in spaced relationship from each other on the respective drive shafts as shown in the end elevation view of FIG. 5. Feed rollers 202 are rotated in a counter-clockwise direction as seen in FIG. 3 while retard rollers 203 are also rotated in a counterclockwise direction as seen in FIG. 3. Thus, if two sheets are in the bite formed by the rollers, the sheet adjacent the feed roller is advanced along the feed path and the sheet adjacent the retard roller is returned toward the stack of sheets.

The coefficient of friction of the material on the periphery of feed rollers 202 should be at least the same as that On the periphery of retard rollers 203. It is preferable, however, that the coefficient of friction of the feed rollers be greater than that of the retard rollers. In addition, it is necessary that the friction between the rollers and a sheet of paper be greater than the friction between adjacent sheets.

In a preferred embodiment, kicker rollers 201, feed rollers 202 and drive rollers 205 have a neoprene material on their periphery. A polyurethane material is used on the periphery of the retard rollers.

The bite between the feed and retard rollers is adjustable. Still referring to FIG. 5, the retard rollers 203 are journaled in casting 230 which in turn is pivotably mounted on shaft 234. Shaft 234 is the drive shaft for gear 245. Gear 245 mates with gear 246 on the retard roller shaft to impart rotation to the retard rollers.

Casting 230 is also shown in FIG. 3. Shaft 231 is used to rotate the casting and hence vary the distance between the feed and retard rollers. Shaft 231 is threaded at one end to mate with threaded extension 233 on casting 230. Shaft 231 is journaled near its other end in bracket 232. Turning shaft 231 permits the casting to be rotated clockwise or counter-clockwise on shaft 234 thereby varying the vertical distance between the feed and retard rollers.

The ability to vary the bite between the feed and retard rollers and to vary the pressure exerted by the kicker rollers on the stack of sheets enables the feeder to feed sheets of several different thicknesses. Of course, adjustments also permit forces acting on the sheets to be varied to optimize the separating and feeding process.

The feeder drive mechanism, shown in FIG. 6, operates in the following manner. Mechanical power for the feeder is supplied by AC synchronous motor 270 which receives its electrical power from the transceiver through connector 265 mentioned earlier. Motor sprocket 271, idler sprocket 272, retard sprocket 273 and drive sprocket 274 support continuous chain 275. The motor shaft turns in a direction to drive chain 275 clockwise as viewed from the right in FIG. 6. The motor runs continuously when the transceiver is in operation. Electrically activated clutch 280 is coupled to the shaft of drive roller 205. Chain 275 and sprocket 274 are operatively connected to one side of the clutch and run continuously. The shaft of drive rollers 205 is operatively connected to the other side of the clutch. Therefore, power is applied to rollers 205 when clutch 280 is engaged. Engaging and disengaging the clutch is controlled by the transceiver logic circuitry.

Clutch 280 controls the application of power to all the rollers except the retard rollers. When the clutch is engaged, power is applied through the drive roller 205 shaft to the chain and sprocket assembly on the left side of the feeder module. Chain 285 rides on top of .drive roller sprocket 28.1. The continuous chain 285 is mounted on idler sprockets 282 and 283 and feed roller sprocket 284. Drive rollers 205 are driven clockwise (rotary direction is determined by viewing the feeder from the right) by chain 275 therefore chain 285 is driven counter-clockwise because it rides on top of drive roller sprocket 281. Both rollers 202 and 205 rotate in the direction of paper feed but because the drive rollers operate from below a sheet and feed rollers from above sheet, the two rollers rotate in opposite directions. Roller 204 is an idler roller.

The retard rollers operate from below a sheet and rotate counter-clockwise to oppose the feeding of sheets along the feed path. The retard rollers receive power from chain 275 through sprocket 273 and gears 245 and 246. Sprocket 273 is rotated clockwise by chain 275. The counter-clockwise rotation of the retard rollers is obtained by gear 235 driving gear 236 in a direction opposite to its rotation.

Chain 290 supported by sprockets on the feeder roller 202 shaft and shaft 259 and timing belt 291 between shaft 259 and the shaft of kicker roller 201 are the means by which power is applied to kicker rollers 201. The kicker rollers rotate in the same direction as the feed roller in order to forward sheets from the stack along the feed path.

The kicker, feed and drive rollers all receive power through electro-magnetic clutch 280. When one of these rollers is rotating so are the other two. The feeding operation is therefore controlled by engaging and disengaging electrically operated clutch 280. Control over the feeding operation is also obtained by raising and lowering the retractable kicker roller by energizing and deenergizing solenoid 250.

The feeding of single sheets to the transceiver feed path is best illustrated by referring to FIG. 3. As mentioned, the kicker rollers 201 are initially in a raised position. The logic circuitry in the transcever generates a start command signal to initiate the feeding process. Power is supplied to the various rollers and solenoid 250 is de-energized to lower kicker rollers 201 into contact with the stack of sheets. The kicker rollers remain in the down position until the top most sheet in the stack, i.e. the sheet engaged by the kicker rollers when lowered into contact with the stack, is driven past rollers 202 and 203 and reaches photodiode 206. Light is directed onto photodiode 206 by light source 207. The transceiver logic circuitry receives a signal from the photodiode when the light is interrupted by the sheet and issues command signals which energize solenoid 250 and stop rotation of the feed rollers. At this point, the logic circuitry initiates a delay period, eg, three seconds, to insure the return of superposed sheets toward the stack by the retard rollers.

Following the three second delay period, the logic circuitry de-energizes solenoid 250 for substantially seven tenths seconds. The kicker rollers momentarily engage the sheet forwarded to photodiode 206 to assist feed rollers 202 to advance the sheet to drive rollers 205. Drive rollers 205 advance the sheet to photodiode 310 in the transceiver, the point just short of transceiver rollers 301. While in this position the sheet is still in contact with drive roller 205.

With the exception of the first sheet fed to the transceiver, the detection of a sheet by photodiode 310 causes power to be removed from drive rollers 205 bringing the feeding operation to a halt. The sheet held at photodiode 310 is separated from the stack, as well as superposed sheets, and is at a position for immediate delivery to the transceiver without fear of a double sheet feed.

The transceiver logic circuitry is informed by appropriately located photodiodes in the transceiver that platen 302 is empty. These photodiodes override the normal function of photodiode 310 causing the first sheet to be loaded directly onto the platen rather than being held at photodiode 310. Simultaneously with the advancement of the first sheet past photodiode 310, a second sheet is separated from the stack by kicker rollers 201 and advanced to photodiode 206. The detection of a sheet by photodiode 206 initiates the three second delay period which provides ample time for the first sheet to be loaded onto the platen as well as insuring the return of superposed sheet toward the stack. At the end of the delay period, kicker roller 201 engages the second sheet for seven tenths seconds assisting the feed and drive rollers to advance the second sheet to photodiode 310. This time photodiode 310 operates in a normal manner by signaling the transceiver logic circuitry to halt the feeding operation. The second sheet is held at photodiode 310 until it is required by the transceiver.

Third and subsequent sheets are loaded onto platen 302 in a similar manner. When the logic circuit commands the second sheet to be driven past photodiode 310, a third sheet is separated from the stack and forwarded to photodiode 206. Following the delay period (and provided the trailing edge of the second sheet clears photodiode 310), the third sheet is advanced to photodiode 310 where it remains until required by the transceiver.

As the last sheet in the stack is being loaded onto platen 302, the kicker roller does not have a sheet toadvance to photodiode 206. Obviously, photodiode 206 fails to detect the presence of a sheet and consequently the logic circuitry is informed that the supply of sheets in tray 220 is exhausted. Thereafter, the logic circuitry turns the sheet feeder off.

Sheet feeder 200 is intended primarily for feeding 8 x 11 inch paper similar in mechanical characteristics to 8 /2 x 11 ream wrapped fine paper employed in every day office use. The present apparatus is modified to handle sheets significantly different in size by altering the dis tances between the various elements of the feeder. As evident from FIG. 1, paper is fed along its short axis because the transceiver changes the direction of sheet movement by 90. In the configuration shown in FIG. 3, the distance between the kicker rollers, while engaged with the stack, the photodiode 206 is substantially five inches, i.e. less than the width of a sheet. Therefore, when a top sheet is forwarded to photodiode 206, the kicker roller is still able to contact the sheet when it is lowered for seven tenths seconds following the three second delay period.

The kicker rollers are activated following the delay period to assist feed rollers 202 to advance the sheet in the bite of the feed and retard rollers past photodiode 206 to drive rollers 205. The period of time the kicker rollers are activated is limited to seven tenths second (or an otherwise appropriate period) to permit the kicker rollers to assist the feed rollers but also to prevent the kicker rollers from forwarding another sheet into the bite of the feed and retard rollers.

During the three second delay period, the kicker rollers are in a raised position and the feed rollers are stopped. However, the retard rollers rotate continuously and since the force exerted on the stack by the kicker rollers is removed, the retard rollers are able to operate more efiiciently in returning superposed sheets toward the stack'in resisting the return of superposed sheets toward the stack,

, use of a delay period improves the performance of the feeder by allowing abundant time for the retard rollers to act on the superposed sheets thereby insuring that only one sheet is advanced to a point where it is available for immediate delivery to the transceiver.

While the invention has been described with reference to its preferred embodiments it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the true spirit and scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teaching of the invention without departing from its essential teachings.

What is claimed is:

1. Sheet feeding apparatus for serially feeding sheets from a stack comprising,

separating means including feed and retard rollers positioned relative to each other to form a bite through which sheets are fed, said feed roller advancing a sheet adjacent thereto along a feed path and said retard rollers returning superposed sheets backward along said feed path,

a switch positioned along said feed path in the direc- 7 tion of feed to detect the presence of sheets in the bite of said separating means,

a retractably supported kicker roller for moving into and out of contact with the stack to forward sheets from the stack into the bite of said separating means,

means for moving said kicker rollers into and out of contact with the stack of sheets in response to electrical command signals,

an electric clutch for starting and stopping rotation of said feed rollers in response to electrical command signals, and

means for generating electrical command signals to remove said kicker rollers from the stack of sheets and stop rotation of said feed roller for a delay period in response to detection of a sheet in the bite of said separating means thereby assisting the return of superposed sheets toward the stack by removing and reducing forces resisting their return and by allowing time to insure the removal of the superposed sheets from said bite prior to advancing a sheet adjacent said feed roller along said feed path.

2. Apparatus according to claim 1 further including a drive roller removed from said switch and positioned adjacent said feed path for advancing a sheet received from said separating means to a point Where it is available for immediate delivery to external apparatus.

3. Apparatus according to claim 2 wherein the distance between said kicker rollers, while in contact with the stack and said switch is less than the length of a sheet in the direction in which it is fed permitting said kicker roller to engage a sheet forwarded to said switch,

said kicker roller, in response to said command signals, engaging a sheet advanced to said switch following said delay period for a period of time sufficient to assist said feed roller to advance a sheet toward said drive roller but not sufiicient to forward a subsequent sheet into the bite of said separating means.

4. Apparatus according to claim 1 wherein said kicker roller is pivotally supported for movement in an arcuate path such that said kicker roller shingles sheets in the stack when pivoted into contact therewith.

5. Apparatus according to claim 4 further including a variable position counterbalance operatively connected to said kicker roller for varying the pressure exerted by said kicker roller on the stack of sheets.

6. Apparatus according to claim 1 further including means for varying the distance between said feed and retard rollers to vary the forces exerted by said rollers on sheets in the bite formed between said rollers.

7. Sheet feeding apparatus of the type wherein sheets are serially fed from a stack comprising,

a retractable kicker roller mounted to move into and out of contact with a stack of sheets to forward sheets from the stack along a feed path,

routing means positioned along said feed path for separating sheets forwarded by said kicker roller, said routing means including an intermittently rotating feed roller and a continuously rotating retard roller, said routing means advancing the topmost sheet forwarded thereto along said feed path and returning superposed sheets toward the stack, and

retracting means operatively connected to said kicker roller for removing said kicker rollers from a stack thereby assisting the return of superposed sheets to the stack by said routing means by removing the force exerted on the stack by said kicker rollers.

8. Sheet feeding apparatus according to claim 7 further including means to stop rotation of said feed roller while said kicker roller is removed from the stack to assist said retard roller to return superposed sheets toward the stack.

References Cited UNITED STATES PATENTS 1,264,053 4/1918 Garner 27138 1,539,918 6/1925 Spiess 271-38 2,734,743 2/1956 Spurlino 27136 3,210,073 10/1965 Godlewski 27136 3,339,917 9/1967 Petrovsky 27136 RICHARD A. SC-HACHER, Primary Examiner 

